Solenoid operated impulse relay



Feb. 18, 1969 w. w. BROCKWAY SOLENOID OPERATED IMPULSE RELAY Filed Maya, 1967 INVEN'TOR. V/LHE L M \J.

.BEOCK WAY fl z g AT TOPNE Y United States Patent Ofice 3,428,924SOLENOID OPERATED IMPULSE RELAY Wilhelm W. Brockway, 16188 MeadowcrestRoad, Sherman Oaks, Calif. 91403 Filed May 8, 1967, Ser. No. 636,778 US.Cl. 335-196 Int. Cl. H01h 1/28 Claims ABSTRACT OF THE DISCLOSURE Adouble-pole relay wherein a spring blade, carrying laterally-spaced dualcontacts on its free end, is actuated by a star wheel which in turn isrotated in steps by successive strokes of a solenoid armature. Forpurposes of assembly and compact design, the spring blade is alignedwith one of the contacts and the other contact is offset laterally fromthe axis of the blade.

Background of invention A relay of the general type contemplated by thisinvention and outlined, above, is disclosed in my prior Patent No.2,547,999. The present invention is an improvement on that patent.

Summary of invention This invention provides an improved arrangement offixed and movable spring contacts wherein a pair of spaced contacts arebridged by a shorting bar comprising two contact fingers on a free endof a spring blade, the contact fingers being of a configuration andpositioning such as to equalize the contact pressures of the two contactfingers against their respective fixed contacts, and to attainsimultaneous make and break of both contact fingers with reference totheir respective fixed contacts.

city of the relay and to avoid any impairment of the spring blade of themovable contact that might result from pass ing current through suchspring blade. To this end, a shortening bar, adapted to bridge betweentwo fixed contacts, formed transversely on the end of the spring blade,carries the current directly between the fixed contacts without thecurrent passing lengthwise through the blade.

Description These and other objects will become apparent in the ensuingdescription and appended drawings, wherein:

FIG. 1. is a fragmentary sectional view of an electric outlet box withthe relay of my invention, shown partially in section, installedtherein;

FIG. 2 is a sectional view thereof on line 2-2 of FIG. 1;

FIG. 3 is a cross-sectional view of the switch unit taken on line 3-3 ofFIG. 1;

FIG. 4 is a sectional view of the switch unit, on line 4-4 of FIG. 1;

FIG. 5 is a detail cross-sectional view of the switch unit, on line 5-5of FIG. 4;

FIG. 6 is a detail cross-sectional view of the switch unit, on line 6-6of FIG. 4;

FIG. 7 is a detail cross-sectional view of the switch unit, on line 7-7of FIG. 4;

3,428,924 Patented Feb. 18, 1969 FIG. 8 is a detail fragmentarysectional view of the star-wheel actuator cam and cooperatingcam-follower.

FIG. 9 is a detail view of the lock spring;

FIG. 10 is a detail view of the holding pawl; and

FIG. 11 is a detail view of the driving pawl.

Referring now to the drawing in detail, I have shown therein, as anexample of one form in which the invention may be embodied, a relaymechanism comprising in general, a solenoid unit A and a switch unit Bin an assembly which is mounted in an electric outlet box '0. Solenoidunit A comprises a cylindrical coil housing 10, a coil 11 and an axiallyslidable armature 12. It is mounted in a knockout aperture of box Cwhich is lined with a rubber grommet 13, and is secured by a lock spring14 having 0pposed jaws gripping the opposide sides of coil housing 10.

The switch unit B comprises a rectangular case 15 of H-section,including a median bridging wall 16 having a window 17 (FIG. 3) and abox frame 18 extending from both faces of wall 16 to define chambers 19and 20 (FIG. 2) on respective sides thereof. In chamber 19 a star camwheel 21 (FIG. 2) is rotatably mounted upon a stud 22 (FIG. 3) fixed inframe 18, and has ratchet teeth in its end faces, engaged by opposedembracing driving ratchet 23 (FIG. 11) and holding pawl 27 (FIG. 10).Driving ratchet 23 has a lever tail pivoted at 24 to the end of armature12 (FIG. 2) whereby star wheel 21 is steprotated by oscillatingmovements of ratchet 23 transmitted from armature 12 as solenoid A isconsecutively pulsed. A coil spring 28, encircling stud 22, is engagedat respective ends with driving ratchet 23 and an adjacent side wall ofcase frame 18, and is torsionally preloaded for return of ratchet 23 andarmature 12 to normal positions shown in FIG. 2 after each pulsing ofsolenoid A. A back cover 25 is clasped onto case 15, to coverchamber,19, the armature 12 projecting through an aperture therein.Switch case 15 has a front cover 29 closing this switch chamber 20.

Chamber 20 encloses the switch contacts, comprising a pair of fixed butyieldable spring leaves 30 and 31 (FIG. 4) mounted on an integral bridgebar 32 traversing case 15 and carrying respective contacts 33 and 34(FIG. 6); and a movable spring blade 35 which is disposed directly belowcontact leaf 30 in registering relation thereto, one end of blade 35being anchored at 36 (e.g. by riveting) to web 16 at one side of window17. The intermediate portion f0 blade 35 extends across window 17 and isengaged by star wheel 21 which extends into the window. The other end ofblade 35 is formed integrally with a transverse shorting bar comprisingrespective fingers 37 and 38 projecting in opposite directions from aneck 39 which joins them to blade 35. Fingers 37 and 38 carry respectivecontacts for engagement with the contacts 33 and 34. Fingers 37 and 38are of equal resiliency and project substantially equal lengths fromtheir junction with neck 39, which is located midway between the sidesof case 115. Thus they engage their contacts against the mating contacts33, 34 with equal yielding action and the make and break is evenlybalanced with respect to both contacts 33 and 34.

Referring now to FIG! 8, star wheel 21 has a plurality of cam teeth 41each having an inclined forward face 42 and a substantially radial backface 43. Switch blade 35 has a cam-follower projection 45 with aninclined forward side 46 and a substantially vertical back side 47.

Between teeth 41, star wheel 21 has respective circumferential dwellshoulders 44 of approximately the same circumferential width as theteeth 41 at their bases. The stroke of driving ratchet 23 is such as torotate the star wheel half the distance between teeth 41 each time thesolenoid is pulsed. The holding pawl 27 and spring 28 cooperate to holdthe star wheel cam in each new the cam in the position shown in FIG. 8,with the nose of projection 45 resting on the nose of a cam finger 41,and intervening pulses will leave the cam 21 in the posi tion shown inphantom in FIG. 8 (and in full lines in FIG. 2) in which the nose ofprojection 45 rests in the corner defined between shoulder 44 and theinclined face of the next tooth 41 following a tooth off of which theprojection 45 has previously dropped. The arrangement provides forspring-urged snap-fall of the projection 45 from the tip of a tooth 41as soon as the back 43 of the tooth has cleared the back side 47 ofprojection 45, free of any retardation by the back 43 of the tooth. Thusthere is maximum rapidity of opening of the contact gap, which minimizesarcing.

Arcing (both on break and make) is further minimized by the balancedloading of the fixed contact elements 30, 31 against the bridge contacts33, 34, and the correspondingly balanced separation which results inboth pair of contacts separating simultaneously. Since contact gap isduplicated at both sides of the switch contact assembly, and since bothgaps are always equalized, the gap dimension is always double that of asingle gap and velocity of contact breaking and inhibition of arcing isat least doubled.

I claim:

:1. In a double-pole stepping relay, in combination:

a solenoid including a coil housing, means to mount the same in aknock-out aperture in an electric outlet box, and an axially slidablearmature;

a switch case of elongated rectangular box form attached to an end ofsaid coil housing and having a median bridging wall dividing theinterior thereof into an actuator chamber and a contact chamber onrespective sides of said wall, said wall having a window intermediateits ends;

a star wheel having circumferentially-spaced cam teeth, rotatablymounted in said actuator chamber, and ratchet means coupled to the endof said armature and cooperable with an end of said star wheel forrotation thereof in steps of half the distance between consecutive camteeth;

a pair of fixed contact elements mounted in said contact chamber andlaterally-spaced positions adjacent respective side walls of said case;

a movable contact element including a spring blade 'mounted in saidcontact chamber alongside one of said side walls in opposed, registeringrelation to one of said fixed contact elements, with one end of saidblade secured to said median wall adjacent one end of said case and anintermediate portion of said blade extending across said window andhaving a follower engaged by said star wheel for deflectio toward saidfixed contacts;

a shorting bar extending traversely on the other end of said movableelement;

a neck joining said shorting bar to the free end of said spring blade inan integral one-piece structure of spring sheet metal, said neckextending transversely from said free end and having an integraljunction with said shorting bar midway between the sides of said case;

said shorting bar comprising a pair of fingers extending transversely inopposite directions from said junction and having substantially balancedflexibility, and

respective contacts on said fingers, positioned for registeringcircuit-closing engagement with said fixed contact elements uponengagement of said follower on the nose of cam tooth on a step ofactuation of solenoid, said spring blade being loaded to withdraw saidcontacts from said fixed contact elements upon a succeeding step ofactuation of said solenoid in which said follower drops into a spacebetween consecutive cam teeth.

2. A relay as defined in claim 1, wherein said fixed contact elementscomprise respective leaf springs each secured to said case at arespective side thereof and each having a projecting flexible portionand a contact at the end thereof in registering relation to the contactsof said bridge.

3. A relay as defined in claim 2, wherein said case includes atransversely extending bridge bar on which said leaf springs aremounted, said bridge bar being spaced from said median wall.

4. A relay as defined in claim 1, wherein said neck extends diagonallyfrom said blade to said junction.

5. A relay as defined in claim 1, each of said cam teeth having aninclined forward side and a substantially radial back side and havingcircumferential, dwell shoulders between said teeth;

said spring blade including a cam follower projection having an inclinedforward side for camming engagement and a substantially radial back sidewhereby said projection may drop from the tip of a cam tooth to anadjacent dwell shoulder without riding against said back side of thetooth thereby increasing break velocity and minimizing arcing.

References Cited UNITED STATES PATENTS 2,532,624 12/1950 Kircher 335-1962,547,999 4/ 195-1 Brockway 335---l 2,600,247 6/ 1952 Huetten 200-16612,788,419 4/1957 Young ZOO-166.1

BERNARD A. GILHEANY, Primary Examiner.

-H. BROOME, Assistant Examiner.

